[PlaneKrazy]

USA, Britain and the free Dutch Navy formed a joint task force in the area to blockade and prevent supply of oil from Borneo and Sumatra in mid 1941. My father was on a tanker called the MV Royal Tiger when Japan attacked Malaya and was witness to the oil blockade.

Roosevelt had effectively strangled japan's economy and from the point of view of the Japanese, they felt they had no other choice. Admiral Yamato who planned the pearl harbour attack foresaw that unless the US Navy was crippled in the opening shots of the conflict, Japan would never win.

USA had significant forces based in the Philappines straddling the trade routes to Indonesia. It was not possible to conceive of taking the oil fields by force and leaving US forces intact.

It is worth noting that the Japanese plan for attacking Pearl Harbour was based upon "War plan Orange" developed by Lt Col John A Lejune USMC and Lt Col Earl H Ellis USMC circa 1932.

This "Opn plan 712" also called for the knocking out of the Panama Canal. A dream Japan clung to throughout WW2 with it's efforts to bomb the Gatun locks. Japan almost secured support from Germany to ship dismantled Stuka dive bombers to Colombia in 1943 for an attack on Panama Canal.

Japan was clearly hemmed in and being cut off from strategic supplies in 1941 and whether we approve of Japan's actions or not, ask any Japanese historian and they will tell you that they viewed the United states as the aggressor in 1941.